Pharmaceutical tablets are typically made of a core of pharmaceutically active material, which is usually white, and a coating applied onto the core. The coating may be colored, i.e., contain ink of a certain color, in order to create uniformly colored tablets. Variations in colored tablets are limited in part by the number of colors potentially usable in coatings. This often leads to situations where different manufacturers have similarly colored tablets which are indistinguishable from one another.
Tablet manufacturers are constantly striving to produce a tablet which is distinguishable from other tablets and thus recognizable by consumers for the purpose of brand development and enhancement. To this end, tablet manufacturers create tablets having different shapes, sizes and appearances including irregular shapes and distinctive colors, and print unique logograms or indicia on the tablets. There are however limits to the sizes and shapes of tablets which can be created, the number of distinctive colors that can be created and the form and type of logograms and indicia that can be created.
The tablets are usually provided with specific colors, logograms and/or indicia in a printing stage. There are several possibilities for printing a medical tablet with ingestible ink. One common technique is pad printing wherein a printing plate is etched with the pattern sought to be printed onto the tablets, ink is placed into the etchings in the pattern and an elastic pad takes up the image from the printing plate and transfers it onto the surface of the tablet. Etched printing plates for use in this printing method, such as those sold by Printing International, Inc., include patterns of uniform etchings to provide a uniform application of the ink to the outer surface of the tablet. As a result, a uniform color is formed on the tablet.
It would therefore be desirable to enable tablets to be formed with color variations or gradients to provide the tablets with distinctive appearances.